Electronic devices, kids and sleep: How screen time keeps them awake

More than two thirds of American men and about half of women say they wish they got more sleep. Poor sleep is linked to higher risk for a host of serious health problems like diabetes, heart disease and depression, and yet the demands of modern society make it harder and harder to get a good night's rest. We work long hours, we stare at the bright screens of smartphones and tablets late into the night, and these bad habits are rubbing off on our kids too.

In 2014, the National Sleep Foundation conducted a poll called "Sleep in the Modern Family," to get a view of sleep habits in American families with at least one school-aged child. Roughly 1,100 parents of children 6-17 years old answered questions about their sleep, their children's sleep, and household rules around bedtimes. Ninety percent of parents surveyed said sleep was important for their family's health, and yet 90 percent also reported that their children slept less than the recommended guidelines. One of the biggest culprits keeping kids awake seems to be the use of electronic devices at night, a bone of contention familiar to any parent of teenagers and preteens.

Kristen Knutson, PhD, assistant professor in the University of Chicago Department of Medicine, served as the polling expert for the NSF. Her research focuses on the links between sleep and health, particularly the role social factors like family routines and electronic use play in sleep quality. She and her colleagues published a study recently in the journal Sleep Health that takes a deeper look at the data in the NSF poll. We spoke to her about what they found, and what parents can do to help their kids get more sleep.

UChicagoMed: Are kids getting enough sleep?

Kristen Knutson: Oh no. No, no, no. The estimate was that 90 percent of parents in the poll reported sleep durations below what we would recommend for children. And that's even after we lowered the bar. The NSF recently published recommended sleep amounts by age group. The recommended amount for 11- to 14-year-olds was nine to 10 hours, and then they dropped that to eight to nine hours for teenagers. That's not to suggest that teenagers need less sleep, I think we're just lowering the bar because we realize getting a teenager to get nine hours of sleep is not going to happen. Even then, 90 percent of the teenagers alone were getting less than 9 hours of sleep.

What are the biggest culprits? Is it really technology?

Technology is a big part of it today, but there is a conflict between biology and society that happens during adolescence and puberty. From a biological perspective, as kids go through puberty their circadian clocks delay. For example there's a circadian rhythm of being able to fall asleep at a certain time. For a child before puberty, 11- to 12-year-olds, that ability falls around 8 or 9 pm. As you go through puberty, the ability to fall asleep occurs later and later. So you may be screaming at your 16 year old to get to bed at 10, even if they tried they may not be able to fall asleep right away.

But at the same time, school start times are getting earlier while their biological clock is telling them to go to bed later. So that's a problem, and their friends are up later too, so they can text or Snapchat with them, which keeps them awake because the light and activity is stimulating. So it's just a perfect storm for making sleep really challenging.

What role do parents play, not necessarily as enforcers of sleep times but role models for their kids?

There were a couple things in the survey that were really surprising. Even if you think about the parent as the enforcer of the rules-the one who says get the cell phone out of the room, turn the television off-at least having these rules was associated with better sleep, even in the teenagers.

Kids look to their parents for behavior and model that, unconsciously or not. So if a parent is sleeping inconsistently, they're not going to grow up respecting the importance of going to bed at a regular time. We asked a question about how often in the past week parents checked email or sent texts after falling asleep. It was a surprising number: A quarter of the people said at least once, and the parents who did that also reported that they thought their kids did it too.

Obviously that's not good for sleep-waking up and shining bright light in your eyes as you're looking at your smartphone or tablet is going to impair your sleep. And there seemed to be a relationship between parents who are short sleepers and kids who are short sleepers. Just like diets are shared, sleep behavior is shared, so they'll model themselves after you.

Is it okay if the phone is in the room but it's just plugged in and charging? Or is there something about the presence of it, knowing it's there and you might get a message?

That should be fine, but if your kid knows it's there and might be tempted to check it in case a friend texts, you might as well charge it in the living room. Even if it's on vibrate, their brains are cued to hear that and it could wake them up. They're going to want to get up and check it, so it's removing the temptation by taking it out of the room.

Is there a rule of thumb for how long before bedtime you should turn off the electronics?

If you could do at least 30 minutes that's great. An hour or more is wonderful, but that's not terribly realistic for a lot of people, including myself. I know the rules and I break them myself sometimes. But give your brain a chance to unwind, to reduce the effects of the bright light and recover from that. Give yourself at least 30 minutes to not be staring at a bright light or doing anything particularly stimulating like playing violent video games. Watching TV from a distance isn't necessarily as bad because it's not as bright, unless what you're doing is very stimulating, so watching a horror movie in bed isn't always a great idea.

Which is more of a problem: the light from screens or the stimulation from using electronics?

Both. Light is particularly bad because it suppresses melatonin. It's also an alerting signal to the brain of it being daytime. It can confuse the brain about what time of day it is. The brain is thinking it should be alert and awake because it's bright and something is going on. So it's doing both at the same time.

What are some top things parents can do to help their kids get more sleep?

Get the electronics out of the room. They're kids, even teenagers are kids, so their impulse control isn't as developed and they are going to be tempted by the phone. Even if you tell them to turn it off, and you watch them turn it off or even turn it off yourself, an hour later if you're asleep they might be tempted to check it and send one more text about something that happened at school that day. If you take it out and charge it in your bedroom-if you can be trusted-then that will help remove the temptation. It might be a battle, but if it becomes the rule every night, that can help.

Teenagers also drink a lot of caffeine these days, so try to minimize how much they have at night. It's a vicious cycle. We know they're not getting enough sleep, and they're trying to get through the school day with caffeine. But you have to try to limit it, especially in the evening.

And just try to talk to them about how sleep is important for health and how well they do in school. There have even been studies that show sleepy people have been judged to be less attractive than not sleepy people-I'm trying to find something that teenagers will care about.

Parents also have to be role models as best we can. Respect your bedtimes and your own sleep, and show the child that it matters, just like eating right and exercising. Try to prioritize sleep when we can, and come up with strategies about what you can do as a family to help.

Matt Wood

Matt Wood is a senior science writer at UChicago Medicine and the Biological Sciences Division.